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Ionogenic fluorescence probes in research of colloidal system
Střondalová, Hana ; Burgert,, Ladislav (referee) ; Mravec, Filip (advisor)
This diploma thesis studied the interaction of ionic and amphiphilic fluorescent probes with polyelectrolytes. The research of such colloidal system could be helpful in deeper understanding of interactions between polyelectrolytes and surfactants. The aim of this thesis was to determine whether ionic or amphiphilic probes are suitable for this research. Two polyelectrolytes, sodium polystyrene sulfonate and hyaluronan were used in this study. Interactions of polyelectrolytes with fluorescent probes (4-Di-2-Asp, methylene blue, dodecyl acridine orange, DiO and DiA) were studied in this work. Then cationic surfactant cetyltrimethylamonium bromide was added to this system. Samples were studied using fluorescence and UV/VIS spectroscopy. Emission and absorption spectra of these probes were recorded. This experiment was based on hypothesis that due to positive charge these probes will bind to the negatively charged polyelectrolyte. Formation of dimers or other aggegates was presumed for fluorescent probes dodecyl acridine orange and methylene blue. When 4-Di-2-Asp was used,changes in fluorescence intensity and absorption spectra in connection with possible formation of aggregates was supposed to be observed. It should be noted that formation of dimers for 4-Di-2-Asp is not described in literature. The formation of dimers wasn't clearly demonstrated during the measurement. Formation of dimers was observed only with dodecyl acridine orange. Probes DiO and DiA were used only in the study of the interaction with polyelectrolytes. These fluorescent probes showed up as inappropriate, because they adsorbed on tube walls. When cationic surfactant was added to hyaluronan-fluorescent probe system, surfactant pushed away fluorescent probe and bonded electrostatically to negatively charged groups of polyelectrolyte.
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Phospholipids as the basis of biodegradable delivery systems
Burdíková, Jana ; Čeppan, Michal (referee) ; Mravec, Filip (advisor)
This thesis is focused on investigation of phospholipid-hyaluronan system. First, appropriate method for preparation of bulk solution of phospholipid/lipid and suitable fluorescence probe were chosen. Sonification was selected as a method for preparation of bulk solution and pyrene was chosen as a fluorescence probe. From the group of phospholipids lecithin was selected. Next to phospholipid, lipid with no phosphate group (DPTAP) was utilized for comparison, alternatively a mixture of lipid (DPTAP) and phospholipid (DPPC). Instead of hyaluronan another polyelectrolytes (sodium polystyrene sulfonate, sodium alginate) were used too. Measurements were performed in water environment and in phosphate buffer saline (PBS). All investigation was accomplished by fluorescence spectroscopy and dynamic light scattering.
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Interactions of aminoclays with natural polyelectrolytes
Jančík Procházková, Anna ; Mravec, Filip (referee) ; Pekař, Miloslav (advisor)
This thesis deals with the preparation of products of interactions of aminoclay with natural polyelectrolytes. Sodium hyaluronate was chosen as the natural polyelectrolyte. The concentration and volume ratio of solutions of aminoclay and natural polyelectrolyte which led to the formation of any type of product were studied. The resulting coagulates were characterized by microscopy, FTIR spectroscopy and rheology. Furthermore the possibility of interactions with fluorescent probes was studied.
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Theranostic systems in sonography
Říkovská, Klára ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This work deals with preparation of microbubble suspension from a mixture of phospholipids, palmitic acid and polyethylene glycol. Properties of prepared systems were studied using bubble tensiometry and dynamic light scattering method and were compared with commercial contrast agent SonoVue®. Suspensions were prepared in various conditions including different atmosphere and increased temperature in some steps of preparation and different solution. Effect of polyethylene glycol addition on surface activity of the system was studied. Surface activity of phospholipids was insignificant. Surface tension decreased with increasing concentration and molecular weight of polyethylene glycol in the system. Effect of different atmosphere and increased temperature showed no substantial trend. It emerged that dynamic light scattering is not suitable for this type of samples because of high polydispersity and phase separation of the system.
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Multiparametric fluorescence spectroscopy
Lacko, Kata ; Venerová, Tereza (referee) ; Mravec, Filip (advisor)
This diploma thesis deals with the possibilities of multiparametric fluorescence spectroscopy, since the main objective of this experiment was to evaluate the possibilities of multiparametric measurements in the fluorescence spectroscopy laboratory. A suitable fluorescence probe was proposed for this type of experiment that shows high sensitivity for pH changes in the environment, SNARF-4F AM, based on a literature research. The fluorophore was dissolved in solutions of different pH and this system was examined using a time-resolved spectrofluorimeter. The method named TRES (time-resolved emission spectra) was used to obtain the emission spectra of the probe and to find the emission maximum. Fluorescence intensity decay measurements as a function of wavelengths allowed to create deconvolution of the emission spectra, which provided information about the fluorescent lifetime and the relative representation of the states of probes in the solution. Later, the probe was dissolved in solutions of different density and pH - this system served for anisotropic measurements, during which the individual correlation-rotational times of the fluorophore were obtained. The obtained results were then used as the basis for multiparametric analysis, which was performed by using a fluorescence correlation microscope and a spectrograph. This combination allows to measure the necessary fluorescence parameters in one step. A standard operating procedure was created for the spectrograph’s control. On the basis of the obtained information the suitability, accuracy and sensitivity of the multiparametric analysis were qualified.
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Incorporation of small organic hydrophilic substances into vesicular systems
Janoušková, Vendula ; Krouská, Jitka (referee) ; Mravec, Filip (advisor)
This bachelor thesis deals with the study of the encapsulation efficiency of hydrophilic drugs and their releasing from the aqueous core depending on the different composition of the components of individual liposomal systems. The hydrophilic fluorescent probe called pyranine was chosen as a model drug. The aim was to prepare liposomes which would be suitable for inhalation administration in terms of their properties. These liposomes would provide passive targeting with prolonged release time without causing negative side effects on the organism. We have succeeded in developing a standard operating procedure for the incorporation of hydrophilic drugs. Liposomal systems have been prepared consisting of the addition of various components as cholesterol, phosphatidic acid, pegylated phosphatidylethanolamine and trimethylchitosan. Furthermore, we were able to characterize the individual liposomal systems in terms of size, stability and encapsulation efficiency which are important physicochemical properties for further application potential.
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Adsorption of biologically active substances in colloidal solutions of aminoclay
Málková, Ivana ; Pekař, Miloslav (referee) ; Mravec, Filip (advisor)
This paper builds on a previous study of magnesium aminoclay and its interactions with biological compounds. The theoretical part deals with the research of the usage of aminoclay as a carrier in medical applications, the method of its formulation, the selection of biologically active compounds and a suitable method of varification. The experimental part deals with the synthesis of aminoclay, samples preparation and study of the adsorption behavior of the selected bioactive compounds under different conditions. The experimental part of the paper also includes varification of the suitability of the selected UV VIS spektrometry to determine the adsorption behavior of the biologically active compounds in colloidal aminoclay solutions.
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Micellar interaction in conditions of phase-separated hydrogel
Lokajová, Aneta ; Sedláček, Petr (referee) ; Mravec, Filip (advisor)
The work aims to study the interaction between hyaluronic acid and the surfactant cetyltrimethylammoniumbromide (CTAB) with proper fluorescent method. Hyaluronan is the strong hydrophilic natur polymer which product viscose solutions with water. It can be found in the joints, skin, eyeball in the live organism. It takes places at cancer growth. It is highly used in cosmetics and medicine because it is nontoxic and biodegradabile. It is used as a aqueous agent or the drug delivery. The work aims to study the interaction with the hydrophobic surfactant with attemption to show or disprove the mutual effect. The emission spectra of pyrene were observed by fluorescence method. The pyren was used as a fluorescent probe.
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Influence of molecular weight of polymers on phase-separated hydrogels
Kolomá, Nikola ; Smilek, Jiří (referee) ; Mravec, Filip (advisor)
This work is focused on study of individual systems of hyaluronan mixtures. All mixtures of hyaluronans they were ready at molecular weights of 15-30 kDa, 80-150 kDa, or 1500-1750 kDa. These individual molecular weights were combined in different ratios most often in ratios of 70:30, 50:50 and 30:70. Septonex surfactant was used for all mixed samples and CTAB was used for last experiment too. At first the gel samples were prepared by a dry route of individual powders with accurately calculated batches. All solutions were prepared wet route with stock of exactly calculated concentration. Physical gels were prepared by combinations of Septonex and hyaluronan with the different molecular weights. In solution formed irregular shapes which we could describe as "marbles" or "beads". After the sample was to stand, the individual „marbles“ of the gel were formed whole mass. Was done too many experiments with physical gels, which has been carried out behavior of mixtures hyaluronans with different molecular weights. All physical and chemical properties were observed by the eye, described and in the and were photographed. Was used hydrophil dye in experiments and served for better visualize comparison samples between themselves. The last experiment was rheological measurement with which is possible characterize viscosity od individual samples.
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Solubilization in sonographic systems
Überall, Martin ; Klučáková, Martina (referee) ; Mravec, Filip (advisor)
The aim of this thesis was to determine the solubilizing capacity of microbubbles based on SonoVue®, and phospholipids SonoVue® is made of, by using the UV-VIS spectrophotometry. The concentrations of solubilized substances within these systems was further determined. In particular, the properties of natrium dipalmitoylphosphatidylglycerole and distearoyl¬phosphatidylcholine were investigated. The microbubbles were produced using these phospholipids with the addition of polyethyleneglycol and palmitic acid. The solubilizing capacity was determined using hydrophobic solutes Sudan Red G, Oil Red O, 4-Di-2-Asp and Nile Red in order to obtain a model system of solubilized drugs or other hydrophobic substances. The behavior of solutes in phospholipids and our prepared microbubbles were examined in a moderately polar medium – physiological saline solution (0.15 M NaCl). The vizualization of prepared microbubbles was performed using optical and fluorescence microscopy. 4-Di-2-Asp, as a fluorescence probe, was not suitable for microbubble vizualization. The size of microbubbles that were produced during the experiment was almost the same as the size of microbubbles of commercially made SonoVue®. The concentration of solubilized hydrophobic solutes inside the liposomes of phospholipids ranged from tens to hundreds of micromoles per liter. With increasing concentration of phospholipids the concentration of solubilized solutes also increased. The results of this experiment can be used for further research focused on the solubilization of drugs in microbubbles, and contrast agents which are used in ultrasonography.
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